Honing device



Sept. 12, 1939. H. 1'. WENDT 2,172,720

HONING DEVICE Filed March 8, 1939 A ttorneus Inventor 7/. 77d flj fT Vndi 6% Patented Sept. 12, 1939 UNITED sTA'ras PATENT OFFICE 3 Claims.

My invention relates to improvements in honing devices for polishing the innerperipheries of the brake drums of automobiles.

As is well known, brake drums are turned to true the same on lathes generally speaking of two types, in one of which the drum is held stationary by a work holder and a tool revolved around the inner periphery thereof by a revolving tool holder, whereas, in the other type the tool holder is stationary and the drum revolved by the work holder about the tool. In both types, the tool holder is adjustable longitudinally of the lathe into the drum and laterally of the lathe to position the tool against the wall of the drum.

l5 The instant invention is designed with the particular purpose in view of equipping such lathes with an inexpensive, highly efficient honing device for polishing the inner periphery of the drum after turning and which is adapted to be attached to the tool holder of such lathes for work upon brake drums of different sizes without necessitating any change in the lathes.

Another objectis to provide a honing device for the purpose above set forth adapted to en- 25 gage the periphery of the drum at two circumferentially spaced points to perform, in effect, successive honing operations substantially concurrently.

Still another object is to provide a device for 30 efiectin such successive honing operations which is adapted for compensating adjustment automatically to maintain the same honing pressures in operation on drums of different sizes.

To the accomplishment of the foregoing, and

subordinate objects presently appearing, a preferred embodiment of my invention has been illustrated in the accompanying drawing, set forth in detail in the succeeding description, and defined in the claims appended hereto.

40 In said drawing:

Figure 1 is a view partly in elevation and partly in transverse section illustrating my improved honing device applied to the tool holder of a lathe and in operative relation to the brake drum.

45 Figure 2 is a view in longitudinal section, parts shown in elevation, of the honing device detached and drawn to an enlarged scale.

Figure 3 is a detail view in transverse section taken on the line 3-3 of Figure 2 looking in the 50 direction indicated by the arrows.

Figure 4 is a View in plan of the hone carrier, and

Figure 5 is a similar View of the driving head.

Referring now to the drawing by numerals, the

55 type of lathe illustrated therein is that in which the tool holder revolves relative to the drum and is adapted to be adjusted to feed the tool holderinto and out of the drum and across the same. Only those parts of the lathe essential to a proper understanding of the invention have been illustrated, .l designating the usual splined shaft for adjusting the tool holder 2 into and out of the drum 3 to be revolved in the direction of the arrow around said shaft by the usual gear drive, (not shown) the tool holder 2 embodying the 10 socket 5, the shank 6 slidably adjustable in. the socket transversely of the axis of rotation thereof under manipulation of the screw feed 7, and the bit or tool-holding arm 8 adjustably mounted in one end of the shank 6 at a right angle thereto and provided with the socket end 9 with a set screw iii thereon for clamping the usual bit or tool in said end. The work holder, or chuck, for the drum together with other parts of the lathe being well known and understood in the art have not been illustrated and need not be referred to 1 herein.

The honing device of my invention comprises an arcuate hone carrier ll of bar-like form and any suitable metal provided in the outer convex face thereof with a pair of transversely extending grooves l2 adjacent opposite ends thereof, respectively, said grooves being transversely square. Apair of hone sockets l 3 of channel form and thin resilient metal are fitted into said grooves 52, respectively, and detachably secured therein by screw bolts M, a pair of which are threaded into said carrier l I from the inner concaved side thereof and into the botttoms of said sockets. A pair of bar-like flat hones i5 of suitable abrasive material are seated in said sockets i3 to extend outwardly therefrom and are clamped between the side walls of said sockets,

said side Walls having a press lit in the grooves i2 whereby they are clampingly engaged with said hones. As will hereinafter more clearly appear, the hone carrier 5 l is designed to be revolved end- Wise in the drum 3 in a direction whereby one hone constitutes a leading hone and the other a trailing one. The hones IE will hereinafter be referred to as leading and trailing hones.

The described hone carrier H is mounted on a substantially T-shaped shorter driving head l5 of bar-like metal, and by means of the following. A pair of stud bolts it are extended through said head l5 adjacent opposite ends thereof, respectively, with the tail ends thereof threaded into the concaved inner side of the carrier ll upon opposite sides of the trailing hone l5, respectively, in the longitudinal center of said carrier. A pair of cushion springs H are sleeved onto said bolts IE intermediate said head I and carrier II and a pair of similar springs I8 are similarly disposed on said bolts I6 intermediate said head I5 and the head ends of said bolts. The springs IT and I3 balance the carrier II on the head I5. As will be seen, by the described arrangement of the bolts 5 5 relative to the carrier I I, one bolt constitutes a leading one and the other a trailing one. The trailing bolt I6 has a sliding pivotal fit in the head I5 and the leading bolt I6 passes through a slot I9 in said head. By this arrangement the trailing bolt I6 constitutes a driving coupling between the head I5 and carrier I I and said carrier and trailing bolt are adapted for yielding pivotal movement on said head I5 as will be clear.

The head I5 is mounted on the end of a shank 20 to swivel thereon and by means of a socket 2I in the end of the stem 22 of said head I5 which receives a ball 23 on one end of said shank. The shank 20 has an enlarged squared part 24 adapted to fit into the socket end 9 of arm 8 to be clamped therein by the set screw I0. A set screw 25 threaded into the stem 22 of the head I5 provides for taking up wear between the described ball and socket joint. A slot 26 is provided in the head I5 for access with a screw driver to the screw bolt I4 that secures the socket I3 of the trailing hone I5 to the carrier II.

Referring now to the operation, with the shank 20 positioned in the tool holder 2 in the manner already described, the honing device is moved into the drum 3 by adjusting the splined shaft I and then toward the inner periphery of the drum 3 by adjustment of the holder 2 under manipulation of the screw feed 1 until the hones I5 engage the inner periphery of said drum and the springs I! are compressed so as to yieldingly thrust said hones I5 against said periphery with the desired pressure. As will be readily apparent, the carrier II and head I5 may pivot freely on the shank 28 universally to engage the hones I5 flush with the inner periphery of the drum 3. Under revolving movement of the tool holder 2 the leading and trailing hones I5 successively polish the periphery of the drum in a manner which will be understood.

Under outward thrust of the described honing device against the periphery of the drum 3 and since the line of thrust is axial of the shank 29 and, therefore, closer to the trailing hone I5 than to the leading hone, said trailing hone will be forced against the periphery of the drum I3 and fulcrumed thereagainst to force the leading hone against said periphery with less pressure than that exerted by said trailing hone. Thus honing under different degrees of pressure is effected, the leading hone performing a perliminary light polishing operation and the trailing hone a finishing operation under greater pressure. The described ball and socket joint ll, 23 provides for compensating movement of the carrier II and head I5 to adjust the hones I5 automatically against drums of different sizes as will be understood from the foregoing.

The construction, operation and advantages of the invention will, it is believed, be readily understood from the foregoing without further explanation. I

Manifestly the invention, as described, is susceptible of modification without departing from the inventive concept and right is herein reserved to such modifications as fall within the scope of the subjoined claims.

What I claim is:

1. In a machine for polishing a brake drum mounted thereon, a tool holder adjustable in the drum crosswise thereof, and a tool comprising a shank mounted in said holder, a head mounted on said shank for universal pivotal movement thereon, a hone carrier yieldingly mounted on said head and of elongated arcuate form, and a pair of flat bar-like hones mounted upon said carrier adjacent opposite ends thereof to be thrust against the inner periphery of said drum under crosswise adjustment of said holder.

2. In a machine for polishing a brake drum mounted thereon, a tool holder rotatable in the drum and adjustable crosswise thereof, a tool comprising a bar-like head, means to mount said head on said holder for universal pivotal movement and rotation endwise in said drum under rotation of said holder, 2. bar-like tool carrier of arcuate form, means to mount said carrier on said head for rotation endwise therewith and for yielding movement thereon, and a pair of leading and trailing hones mounted on said carrier adjacent opposite ends thereof, respectively, to be yieldingly thrust against the inner periphery of said drum under crosswise adjustment of said holder.

3. In a machine for polishing a brake drum mounted thereon, a tool holder rotatable in said drum and adjustable crosswise thereof, a tool comprising a shank mounted in said holder, a T-shaped driving head of elongated form having a central boss pivotally mounted on said shank for universal swinging movement of the head on said shank and for rotation endwise in said drum, an arcuate bar-like hone carrier, means to mount said carrier on said head for rotation endwise thereby, and a pair of leading and trailing hones mounted on said carrier adjacent opposite ends thereof, respectively, said means comprising a pair of bolts slidably extending through said head adjacent opposite ends thereof, respectively, and threaded into said carrier upon opposite sides of said trailing hone, respectively, in the longitudinal center of said carrier, tension springs on said bolts intermediate said carrier and head, and similar springs on said bolts intermediate the free ends thereof and said head.

HENRY 'I'. WENDT. 

